Piston with oil return passage and engine

ABSTRACT

A piston with an oil return channel may include a piston head, a piston skirt, and an oil return hole. The piston head may include a ring groove. The piston skirt may be connected to the piston head. The piston skirt may have a surface including a concave face window. A connection between the face window and the ring groove may form a residual ring bank. The oil return hole may be formed by milling on the residual ring bank. The oil return hole may connect the ring groove close to the piston skirt with the face window. A depth of the oil return hole may be greater than a depth of the ring groove.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No. CN202122733618.7, filed on Nov. 9, 2021, the contents of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The utility model relates to the field of engines, in particular to apiston and an engine with an oil return channel.

BACKGROUND

As one of the core components of the engine, the piston of the engine isfacing the challenge of higher durability and reliability. Thedurability of the piston is one of the most important factors affectingthe reliability of the engine. Improving the initial and low engine fuelconsumption under the durability life can well ensure that it meets therequirements of emission regulations in the whole life cycle. The designof oil return hole, as an important link to reduce oil consumption anddurability, needs to be reasonably designed to improve the ability ofoil return.

As shown in FIG. 1 and FIG. 2 , the existing design of oil return hole,but its effective oil return section is too small, resulting in: the oilreturn hole set at the upper end of the skirt is unfavorable to reducingthe oil consumption at low speed and low load, and more oil willaccumulate at the upper end of the skirt and even be sucked up; The oilreturn section is small, and the large amount of oil backflowencountered at high speed and high load is unfavorable.

As an improvement, an improved oil return hole is introduced in thepatent Publication No. CN202832824U, which sets the oil return hole onthe third annular bank and communicates with the surface window tofacilitate oil return; In the patent Publication No. CN208935361U, theupper surface of the skirt of the piston body 1 is integrally formedwith an oil storage tank 7. In the actual cast or forged piston, the oilstorage tank is machined, and the lower end of the second oil returnwindow 8 is integrally formed with a stub shaft platform 9. The shortaxis platform in the structure is obviously more protruding than theface window, so it is difficult to cast directly.

SUMMARY

In view of this, the disclosed embodiments provide a piston with an oilreturn passage and an engine to solve the problems in the prior art.

In order to solve the above technical problem, the present inventionprovides a piston having an oil return channel, the piston including:

Piston head, the head is provided with a ring groove;

Piston skirt, the skirt is connected to the head, the surface of theskirt is provided with a concave face window, and the connection betweenthe face window and the ring groove forms a residual ring bank;

Oil return hole, the oil return hole is formed by milling on theresidual ring bank, the oil return hole connects the ring groove closeto the skirt with the face window, and the depth of the oil return holeis greater than the depth of the ring groove.

Furthermore, the size of the opening of the oil return hole is largerthan the size of the bottom of the oil return hole.

Preferably, the axis of the oil return hole extends along the radialdirection of the piston.

Preferably, a plurality of oil return holes are arranged, and aplurality of oil return holes are symmetrically distributed on theremaining ring bank.

Preferably, the difference between the depth of the oil return hole andthe depth of the ring groove is 0.5-1.0 mm.

Preferably, the diameter range of the bottom of the oil return hole is Ø8 mm- Ø 15 mm.

Preferably, the ring groove comprises at least one gas ring groove andat least one oil ring groove, the gas ring groove is located above theoil ring groove, and ring banks are arranged between the gas ring grooveand the top of the head, between the gas ring groove and the oil ringgroove, and between the oil ring groove and the skirt.

Preferably, the gas ring groove is a wedge-shaped ring groove or arectangular ring groove and is internally provided with an air ring, theoil ring groove is a rectangular ring groove and is internally providedwith an oil ring and an oil ring support spring.

Preferably, the annular groove includes one gas ring groove and at leastone oil ring groove at least, and the gas ring groove is located oilring groove top, all is equipped with the land between gas ring grooveand the top of the head portion, between gas ring groove and the oilring groove, between oil ring groove and the skirt portion.

Preferably, the gas ring groove is a wedge-shaped groove or arectangular groove and is internally provided with a gas ring, and theoil ring groove is a rectangular groove and is internally.

In a second aspect, an engine provided by the embodiment of the presentinvention further includes the above-mentioned piston having the oilreturn channel.

The piston with the oil return channel and the engine have theadvantages that:

The beneficial effects of a piston and an engine with an oil returnchannel of the utility model are:

1. The application adopts the milling method at the position of theremaining annular bank, and processes the oil return hole with circularopen section with one feed. The opening size of the oil return hole islarger than the size of the bottom of the oil return hole, which greatlyincreases the area of the oil flow section and at least doubles the areaof the oil flow section; The processing method of one-time feed millinghas a simple processing path, which greatly reduces the production costand improves the processing speed;

2. The opening size of the oil return hole of the application is largerthan the size of the bottom of the oil return hole, and is connectedwith the face window, so that the oil is not easy to accumulate in theoil return hole, and the oil accumulated in the oil return hole is noteasy to be sucked back to the combustion chamber when the engine runs atidle speed or low speed and low load, so as to reduce oil consumptionand improve exhaust emission;

3. The depth of the oil return hole described in the application isgreater than the diameter depth of the third ring groove, which reducesthe risk of burr and avoids the risk that steel chips are not easy tocome out during processing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of an oil return hole in the prior art;

FIG. 2 is a side sectional structural diagram of FIG. 1 ;

FIG. 3 is the structural diagram of the piston with oil return channelof the utility model;

FIG. 4 is a sectional view of the head of the piston with an oil returnchannel of the utility model; and

FIG. 5 is a schematic cross-sectional view of the oil return hole of thepiston with an oil return.

DESCRIPTION OF SYMBOLS

10 head; 11 first ring groove; 12 second ring groove; 13 third ringgroove; 14. The first ring bank; 15 second ring bank; 16 Third Ringbank; 17. Residual ring bank; 18 gas ring; 19 oil ring; 110 oil ringsupport spring; 111 oil return hole;

20 skirt; 21 face windows.

DETAILED DESCRIPTION

The function of the oil return hole is to effectively return the oil inthe cylinder to avoid the carbonization of lubricating oil such as oiland adhering to the piston ring groove or combustion chamber, affectingthe engine performance and reducing the service life of the engine.Therefore, as an important means to reduce oil consumption anddurability, the oil return hole needs to be reasonably designed toimprove the oil return capacity. As shown in FIGS. 3 to 5 , thisembodiment provides a piston with an oil return channel, including ahead 10 and a skirt 20 connected with it. The head 10 is provided with aring groove, the surface of the skirt 20 is provided with a concave facewindow 21, and the connection between the face window 21 and the ringgroove forms a residual ring bank 17; At least one oil return hole 111is arranged on the remaining annular bank 17.

Specifically, the head 10 and the skirt 20 are cylindrical andintegrally formed.

The piston with oil return channel is a steel piston.

More specifically, as shown in FIGS. 4 and 5 , the ring groove includesa first ring groove 11, a second ring groove 12 and a third ring groove13. The first ring groove 11 is close to the top of the head 10, thethird ring groove 13 is close to the skirt 20, the second ring groove 12is located between the first ring groove 11 and the third ring groove13, and a first ring bank 14 is formed between the top of the head 10and the first ring groove 11, A second annular bank 15 is formed betweenthe first annular groove 11 and the second annular groove 12, a thirdannular bank 16 is formed between the third annular groove 13 and theskirt 20, and the third annular bank 16 is communicated with theremaining annular bank 17.

The first ring groove 11 is a wedge-shaped or rectangular ring groove,the second ring groove 12 and the third ring groove 13 are rectangularring grooves, the first ring groove 11 and the second ring groove 12 areprovided with an air ring 18, and the third ring groove 13 is providedwith an oil ring 19 and an oil ring support spring 110.

The diameters of the second annulus 15 and the third annulus 16 aregreater than those of the first annulus 14.

Because the piston is a steel piston, the first ring groove 11, thesecond ring groove 12 and the third ring groove 13 can withstand higherstrength collision and friction, the piston can withstand higherexplosion pressure and the service life of the piston is longer.

Specifically, as shown in FIG. 3 , the oil return hole 111 is formed bymilling on the remaining annular bank 17, and the opening size of theoil return hole 111 is larger than the size of the bottom of the oilreturn hole 111.

The application adopts the milling method at the position of theresidual ring bank to process the oil return hole with circular opensection with one feed. With a simple processing path, the whole new formof oil hole manufacturing has a certain cost advantage. As shown in FIG.5 , the piston greatly increases the area of the oil flow section, atleast doubling the area of the oil flow section.

The difference between the depth of the oil return hole 111 and thediameter depth of the third ring groove 13 ranges from 0.5 to 1.0 mm.The diameter range of the bottom of the oil return hole 111 is Ø 8Ø 15.

The risk of burr is reduced during piston processing, and the risk thatsteel chips are not easy to come out during processing is avoided.

The oil return holes 111 are provided with a plurality of oil returnholes, which are symmetrically distributed on the surface window 21, andform a plurality of remaining annular banks 17.

In the specific embodiment of the application, the skirt 20 is providedwith two relatively arranged face windows, and two remaining annularbanks 17 are formed, and two oil return holes 111 are evenly distributedon each remaining annular bank 17.

During the specific implementation, the oil can flow to the face windowthrough the oil return hole to form an oil return channel, and then flowto the oil pan. The oil is not easy to accumulate in the oil returnhole. When the engine is idling or running at low speed and small load,it is not easy to suck the oil accumulated in the oil return hole backto the combustion chamber, so as to reduce the oil consumption andimprove the exhaust emission.

In specific implementation, a plurality of evenly distributed oilstorage holes can also be arranged at the circumferential position ofthe third ring groove 13.

In the second aspect, the embodiment of the present disclosure providesan engine, which also includes the piston with oil return channel.

During the implementation of the application, when the piston moves backand forth, the piston plays the role of oil scraping and oildistribution. For example, the application defines the direction closeto the head 10 as above and the direction close to the skirt 20 asbelow. When the piston moves from top to bottom, the second ring bankscrapes the oil to the oil return hole and then flows to the face windowto form an oil return channel; When the piston moves from bottom tobottom, the oil is distributed around the bank.

1. A piston with an oil return channel, comprising: a piston headincluding a ring groove; a piston skirt connected to the piston head,the piston skirt having a surface including a concave face window, aconnection between the face window and the ring groove forming aresidual ring bank; and an oil return hole formed by milling on theresidual ring bank; wherein the oil return hole connects the ring grooveclose to the piston skirt with the face window; and wherein a depth ofthe oil return hole is greater than a depth of the ring groove.
 2. Thepiston according to claim 1, wherein a size of an opening of the oilreturn hole is larger than a size of a bottom of the oil return hole. 3.The piston according to claim 2, wherein an axis of the oil return holeextends along a radial direction of the piston.
 4. The piston accordingto claim 3, further comprising a plurality of oil return holes includingthe oil return hole, wherein the plurality of oil return holes arearranged symmetrically distributed on the residual ring bank.
 5. Thepiston according to claim 1, wherein a difference between the depth ofthe oil return hole and the depth of the ring groove is 0.5 mm to 1.0mm.
 6. The piston according to claim 1, wherein a diameter range of abottom of the oil return hole is Ø 8 mm to Ø 15 mm.
 7. The pistonaccording to claim 1, further comprising a plurality of ring banks,wherein: the ring groove includes at least one gas ring groove and atleast one oil ring groove; the at least one gas ring groove is disposedabove the at least one oil ring groove; and the plurality of ring banksare arranged between the at least one gas ring groove and a top of thepiston head, between the at least one gas ring groove and the at leastone oil ring groove, and between the at least one oil ring groove andthe piston skirt.
 8. The piston according to claim 7, wherein: the atleast one gas ring groove is at least one of a wedge-shaped ring grooveand a rectangular ring groove, and is internally provided with an airring; and the at least one oil ring groove is a rectangular ring grooveand is internally provided with an oil ring and an oil ring supportspring.
 9. An engine, comprising the piston according to claim
 1. 10.The piston according to claim 1, further comprising at least one gasring groove and a plurality of ring banks, wherein: the ring groove isan oil ring groove; the at least one gas ring groove is disposed betweena top of the piston head and the oil ring groove; and the plurality ofring banks includes: a first ring bank arranged between the at least onegas ring groove and the top of the piston head; a second ring bankarranged between the at least one gas ring groove and the oil ringgroove; and a third ring bank arranged between the oil ring groove andthe piston skirt.
 11. The piston according to claim 10, furthercomprising: a gas ring arranged at least partially in the at least onegas ring groove; an oil ring arranged at least partially in the oil ringgroove; and an oil ring support spring arranged in the oil ring groove.12. The piston according to claim 10, wherein a diameter of the secondring bank and a diameter of the third ring bank are greater than adiameter of the first ring bank.
 13. The piston according to claim 1,further comprising a plurality of gas ring grooves, wherein: the ringgroove is an oil ring groove; and the plurality of gas ring groovesincludes: a rectangular-shaped gas ring groove; and a wedge-shaped gasring groove.
 14. The piston according to claim 1, wherein the surface ofthe skirt is an outer circumferential surface.
 15. The piston accordingto claim 1, wherein: a difference between the depth of the oil returnhole and the depth of the ring groove is 0.5 mm to 1.0 mm; and adiameter of a bottom of the oil return hole is 8 mm to 15 mm.
 16. Apiston with an oil return channel, comprising: a piston head including aplurality of ring grooves; a piston skirt connected to the piston head,the piston skirt having a surface including a concave face window; aresidual ring bank arranged between the face window and a ring groove ofthe plurality of ring grooves disposed closest to the piston skirt; andat least one oil return hole disposed in the residual ring bank andfluidically connecting the ring groove and the face window; wherein adepth of the at least one oil return hole is greater than a depth of thering groove.
 17. The piston according to claim 16, wherein the at leastone oil return hole includes a plurality of oil return holes that aredisposed evenly distributed along the residual ring bank.
 18. The pistonaccording to claim 16, further comprising a plurality of ring banks,wherein: the ring groove disposed closest to the piston skirt is an oilring groove; the plurality of ring grooves includes a gas ring groovedisposed between a top of the piston head and the oil ring groove; andthe plurality of ring banks includes: a first ring bank arranged betweenthe gas ring groove and the top of the piston head; a second ring bankarranged between the gas ring groove and the oil ring groove; and athird ring bank arranged between the oil ring groove and the pistonskirt.
 19. The piston according to claim 18, further comprising: a gasring arranged at least partially in the gas ring groove; an oil ringarranged at least partially in the oil ring groove; and an oil ringsupport spring arranged in the oil ring groove.
 20. The piston accordingto claim 16, wherein: the ring groove disposed closest to the pistonskirt is an oil ring groove; the plurality of ring grooves includes: arectangular-shaped gas ring groove; and a wedge-shaped gas ring groove.